Sony TC-788-4 Setup guide

DUN Ke
4 CHANNEL STEREO TAPECORDER ~..
TC-788-4
°
OWNER’S INSTRUCTION MANUAL
Precision, uncompromising quatity, and superb quadraphonic or
sstereophonic sound... they are now yours with the exciting Sony
To-788-4,
Spoctal features ar.
415 ips, 10¥/2-inch reel, 4-track 4-channal
operation.
Ac servo-controllad capstan drive motor which provides constant
speed regardless of voltage or load changes.
‘#*Closad-loop dual capstan tape drive which assures postive tape-
to-head contact and isolates external vibration
eLogic-controited function buttons which allow feather-touet,
direct transport switching from any mode to another mode,
Provisions for timer-controlled recording or playback
‘Separate tape equalization and bias salector switches to optimiza
tho characteristics of any tape.
‘*PAN POT (panoramic potentiometer) facility which enables back-
to-trant channol mixing, especially useful for mutt-mie stereo
recordings.
‘¢Synenro-track foeiity 10 allow synchronized recording of new
‘tracks with previously rocordad tracks.
‘#Direct coupling of the playback head 10 the FET in the first stage
of the playback amplifier, resulting ia better signal-to-noise for service-use onl
characteristics.
Please read these instructions carefully to obtain maximum per
formance and enjoymant from your TC-788-4. The tlexiili
provided by its many faatures may not be fully appreciated unless
‘you spond’a little time gaining familiarity with its controls and
facilities. Keep this manual handy for future reference,
jeording and playback
WARNING OWNER’S RECORD
To avoid electrical shock, do not open. the — Fer your convenience, record the model number and serial number
{you will find them on the rear of your unit) in the space provided
cabinet. Refer servicing to qualified personnel pelow. Please refer to thom whan you contact your Sunerecope
only. Service Station in case of dificaty. This wil Be @ great help to
you in getting better end more satisfactory service on your unit.
To prevent fire or shock hazard, do not expose
the set to rain or moisture.
Model No. TC-788-4 Serial No.

TABLE OF CONTENTS
SPECIFICATIONS ........
FREQUENT CLEANING OF HEADS RECOMMENDED
PRECAUTIONS . fe
UADRAPHONIC SOUND
CONNECTIONS...
FUNCTION AND LOCATION OF PARTS AND CONTROLS .
‘Amplifier Section
Tapestransport Section
TAPE THREADING. .....-.....--.-- b
RECORDING AND PLAYBACK a
Fundamental Steps
4-Channe! Recording
‘2-Channel Recording
Playback (¢ CH, 2 CH)
Mone Recording and Playback
Erasing Tape
RECORD LEVEL ADJUSTMENT . oe 14
SPECIAL, OPERATIONS... 18
Micraphone and Line Mixing
‘Mixing with the Use of the Panoramic Potentiometer
Synchro-track Recording
‘Timer-activated Recording
About Tracks and Channels
EDITING. 2
Duplicating Procedure
Cuoing Procedure for Splicing
Splicing Tape
MAINTENANCE.
Clanning Heads and Tape Path
Domagnetizing Heads
Lubrication
Cleaning of the Cabinet
TROUBLE SHOOTING GUIDE...
20
SPECIFICATIONS
Power requirements: 120 volts AC, OH:
Power consumption: 120 watts
Tape speeds: 1Bips, 71/2ips
Recording time: 4-channel stereo recording:
fwith 3,600 ft tape} 45 minutes at 15 ips
90 minutes at 71/2ips
2-channel stereo recording:
80 minutes at 1Sins
180 minutes at 71/2ips
Mone recording:
180 minutes at 18 ips
360 minutes at 71/2/ps
2 min, 30 seo. with 2,400 tape
Fast winding time:
(tOt/2-inch reel)
Reels: 101/2 inches or smaller
Track system: 4-track 4-channet stereo recording and
playback
4-track 2-channel stereo
4-track mono
Heads: } record head, 1 playback heed,
Vorase head
Motors: Ac servo-controlted capstan motor: ......1
I motors
Bias frequency :
Equalization: NAB standard
Signa!-to-noise ratio: 56 ¢8 (SLH tape)
5348 (standard tape}
Harmonic distortion: 1.2%
Frequency responsa: With SL ta
20~26,000 Mz at 15 ips
30 ~ 28,000 He3 dB at 18 ips
20~28,000 He at 71/2ips
90-23,000 Hz 3.48 at, 71/2 ine
With standard te
20- 30,000 Hz at 18 ips
20- 23,000 Hz at 71/2 ips.
0.04% at 15 ips, 0.06% at 71/2 ips, WRMS ‘Wow and flutter:
Inputs: MIC inputs.....es..+ss++04 (phone jacks)
Sansitivity 0.2 mV {=72 48)
Accept low impedance microphones
LINE INputs «0. 4
Sensitivity 0.06 V {--22 dB)
Impedance 100 ka
Outputs LINE OUTputs
Outpot level 0.43 V {6 dB) at toad
impedance of 100 kO with the PB LEVEL
‘control in center click position (PB LEVEL
control set ta MAX: 0.775 V=0 dB)
Suitable load impedance--higher than
tok
HEADPHONE jacks 2
Accept 80 stereo headphones,
AC outlet: Unswitehed 1 {300 W maximum)
Dimensions: 173jetwh x 22{h} « B3}eld) inches
Weight: 68 lb 702
‘Supplied accessories:
1OMzinch reel... 1
Reel adaptor RAD-10 2.2
Connecting cord RK-74H........2.4
1
1
1
Head cleaning ribbon... a
4-channel demonstration tape ...-
AC power cord.
2 subject to change without notice.

FREQUENT CLEANING OF HEADS.
RECOMMENDED
eThe bast performance of your TC-788-4 depends on your
petiodic cleaning of the heads and ail surfeces over which the
tape travels. Cleaning should be done after every 10 hours of
operation,
For details refer to the “ MAINTENANCE” section on
Clean head
FREQUENCY RESPONSE [et 15ins)
T TOT 7
oy stem hese
Hy rset
By ary mead AL
ih Lf LE ES
Output love in 6
LT Even hacaty visiote | \
7 Hil
H
|] aosttaver of 1.5e \
oF 1 13
Udetorioraws freavency
Frequeney in He
Playback wavetorm at 10 KHz
By eloan head
By dirty head
‘The output tevel
fucwates
It you hava any problem with your recorder. consult your nearest
Superscope Service Station.
PRECAUTIONS
Safety
‘@ Operate only on 120 AC, 50 He.
‘@Shoutd any liquid or solid object fall into the mechanism, unalug
the set and have it checked by qualified personnel before oper-
ating It any further.
‘*Unpiug the set from the wall outiet when
for an extended period of time.
‘#To disconnect the cord, pull it out by the plug
the cord.
Is not to be used
Never pult it by
Installation
‘eThe TC-788-4 is designed for vertical operation only.
‘® Good air circulation is essential to prevent internal heat build-up.
Be careful to select a position which allows adequate air circula~
tion, Do not place the sat in an enciosure—ike shelf that would
‘block the ventilation grilles at the back, top. or sides of the set.
Never place anything on top of the cabinet,
#0 not install the set in @ location near hest sources such as
radietors and air ducts or in a place subject to direct sunlight,
‘and protect it against excessive dust, mechanical vibration, and
shook.
Operation
@ Lock tha reals before operating.
‘*Thread the tape without slack and set the tension arms In oper
‘ating position,
‘eMC and LINE sources can be used simultaneously for mixing,
‘but if you want to record only one of thom, turn the feval control
cof the undesired input fully counterclockwise,
‘The following control So koep them in
their normal positions until otherwise stated, and check ther
trom time to time to prevent operation errors:
@ During normal use keep the REC TIMER LOCK lever in the
upper position. This lever should never be used except for
timer-sotivated automatic recording.
® Be careful not to move the REC MODE switches while
recording.
@ Keep the MIC ATT switchas OFF (pushod-in ‘position of the
MIC REC LEVEL controls).
@ Bo aure to turn the PAN POT switch to OFF, if this feature is
not wanted.
® Keep the HEADPHONE ewitch in the 4 CH (2 CH) position.
© Keep the PB LEVEL controls in the center position,

QUADRAPHONIC SOUND
Quadraphonic sound permits the accurate reproduction of music
a itis heard in a concert hall and gives you the feeling of bsing
iramersed and surrounded by sound. 2-channel systems, even in
‘an acoustically ideal living reom, cannot reproduce tha ambience
and radiation of a good auditorium because of their difference in
oom siz and the limitation of the sound source to two diman-
sions. Quadraphonie systems open the third dimension by adding
two channels ‘to the existing two front channels providing the
separately recorded, reflected sound of 2 large hall, and thus
create the special characteristics and ambience pattern of 8 fine
concert hall in your living room.
Furthermore, for popular music, quadraphonic systams permit
Ingtrumants to be lacatsd to the back and sides of the listener,
‘creating the ilusion of being in the center of the musicians, and
thus opan the possibilities to a large number of surprising effects.
CONNECTIONS
‘While making connections, observe tha following notes:
‘#Turn off the amplifier while making connections.
‘insert the cable connectors completely into the Jacks. Loose
connections may cause hum and noise.
‘*For high quality recording use the supplied connecting cords ;
use th red plugs for the right-channel connections and the
remaining plugs for the left-channal connections.
‘eAnach the supplied cord labels to each cord as this simplifies
later checks.
Amplifier connection
For playback connect the recorder LINE OUTputs to the amplifier
tape inputs for discrete or auxiiary inputs). Fer recording con-
neet the recordar LINE INputs to the amplifier recording outputs.
For conventional stereophonic recording or playback only the front
‘ehannel connections are needed,
channel decoder connections
LINE our
Faonr
LINE IN
BACK
ro line
outputs
tre
fh
Bhs
seit
. :
‘
:
Tuner Front Record player
abs speaker

‘Tape duplication connection
A4-channel tape duplication
itd
cord labot
2echannel amplifier connections
une oT
Back
LINE Int
Ack
FRONT
sae
‘
cd
e ? 5
cbined
—
Ee carn tae
a
Ser
2-chennel tape duplication
10 FRONT LINE
OUTpULs
10 tape inputs
|
to FRONT LINE
Wopurs
Recording
to recording outputs
4
TAPE
REC OUT
2-channal amplifier
TC-788-4 ‘LINE.OUT URE IN
.
} 9-6
Duplication
las
Zito oor pu
‘Duplication from
To fine outputs. nether recorder
Power connections
‘Connact the AC INput to a wall outlet of 120V AC by
supplicd AC power cord.
The
AC
OUTLET
is
designed
to
cupply
AC
power
(maximum
300
watts}
to
other
components
such
as
2
turntable,
ete,
This
outlet
is
not
controllad
by
the
front
panel
POWER
switch.
using the
Ground connection
it
hum
occurs,
it
may
be
helpful
to
connect
the
ground
terminal
[a] to en eppropriate external ground.

FUNCTION AND LOCATION OF PARTS AND CONTROLS
Amplifier section

D RECord button
1 recording, fully depress this button, and while holding it de-
pressed push the J button, The red lamp in the button will light
indicating that the recorder is in record mode.
@ REC TIMER LOCK lever
During aormel operation this lever should be in the upper position.
For timer-activated recording slide it down after pushing the REC
button, and the TG-788-4 will record (ond erase} any time the
> button is pushed.
@ FRONT REC LEVEL controls
‘The left controls aro for the left front channel, and the right for
the right front channel. The larger knobs adjust the recording
Jevel of the corresponding LINE INputs, and the smalfer ones
adjust the level of the MIC inputs. Excessively high microphone:
input signals may be attenuated by pulling the MIC contrals out
wards [PULL ATT 20 dB). Normally, however, they should be kept
pushed inwards.
@ Equalization selector (E03
Select the bost equalization characteristics for the tape used, in
both racord and playback modes. Recommended EQ settings for
listed on page 10.
@ MIC jacks
‘Any high quaiity low-impedance microphone equipped with @ phone
plug may be os
priate front and back inputs.
For
stereo
racording
with
more
than
2
microphones
use
the
front
inputs
for
the
extreme
right
and
left
positions,
and
the
beck
inputs:
{or
the
positions
in
betwaen
of
the
reflected
sound,
while
switch-
ing
the
PAN POT
switch
on
(refer
to"
Mixing
with
the
Use
of
the
Panoramic
Potentiometer
[PAN
POT”
on
page
16).
sphonie Tecording use the appro~
@ REC MODE switches
‘Select the tracks to be recorded by setting these switches to REC.
Red lamps in the corresponding VU-meters will Iiuminate indicating
that the channel is ready for racording. For playback set the
switches to the PB position. For synchro-track recording set the
switch(ed) of the prerecordad track(s) to SYNCRO TRAK, and those
‘of the tracks to ba recorded to REC.
@ MONITOR switches
For playback set these selectors to TAPE, and for record level
adjustment sat them to SOURCE, While recording, tape monitor-
ing is possible st TAPE, and source monitoring et SOURCE.
© Panoramic potentiometer switch {PAN POT}
During normal operation this switch should be set to OFF.
Set this switch ON to feed back-channel input signals to the front
channels. The graen PAN POT lamp will light to remind you that
‘the panoramic potentiometars are activated
@ Pancramie potentiometer controls [PAN POT)
‘To feed the input signals of one of the back channels to the left
front
channel,
turn
the
corresponding
PAN
POT
control
to
LF.
To
convey
these
signals
to
the
right
front
channel,
set
the
control
to
RF. The center click position, marked C, directs the added sound
source t0 the center front position. These controts allow the
acoustical positioning of one or two mono sound sources between
the left and right front channel positions.
@ BACK REC LEVEL controls
They function in exactly the same manner as the FRONT REC
LEVEL controls to regulate the back channel record volume,
® HEADPHONE outputs end
® HEADPHONE switch
‘Any high quality 8-ohm stereo headphones {two or four channels}
equipped
with
2
standard
binaural
phone
plug
ean
be
connected.
With
the
HEADPHONE
switch
set
to
4
CH
(2
Ch),
the
Front
head
phone
output
provides
the
front
channel
(LF
and
RF)
sounds
or
the
left
and
right
sounds
in
stéreo
recording
or
playback,
while
the Back headphone output provides the back channel sound (LB
‘and Re} in quadraphonic recording or playback.
In the F+B position of the headphone switch the front and back
sounds
of
the
left
channels
can
be
heard mixed
in
the
left
head=
phone,end
those
composed
of
the
front
and
back
right
channels
in
the right headphone, independent of whether the connoction Is
made to the front o back haadphone output.
When
the
headphone
switeh
is
set
to
MOND,
the
sounds
of
all
four
tracks
are
mixed
together
and
can
be
heard
on
either
chann«
right
or
left,
front
oF
back,
© POWER switch
© Playback Jevel controls {F PB LEVEL ond 8 PB LEVEL)
Thase knobs adjust the playback signal level at the LINE OUT and
the HEADPHONE jack, which ere also shown on the VU-met
when the monitor switch is set to TAPE. A O-VU reading corr
‘sponds
to
an
output
voltage
of
0.43V,
During
normal
uso
set
the
smater knob (R channel} to the canter click position and align the
larger knob with the other one. If the level is 100 high or too
Jow,
adjust
these
knobs:
fuil
clockwise
rotation
will
provide
5
48
boost, and full counterclockwise rotation will muta the sound.
@ VU-meters
‘With
the
monitor
selectors
get
to
SOURCE,
the
meters
show
the
recording
level,
with
the
selectors
set
to
TAPE,
the
meters
show
the
output
level
et
the
LINE
OUT
and
HEADPHONE
jacks
;
0-VU
reading
corresponds
to
0.43
volt.

Tape-transport section
© Tope-height adjusters
If the tape rubs 2 reol edge, the tape height can be slightly
adjusted with thasa screws; clockwise rotation witt bring the tape
closer to the front reel edge, and counterclockwise rotation oloser
to the rear adige. Before adjusting check both eupply and take-up
reels, If thoy are warpad, replace them
@ Tension armas
If both arms are horizontal, the tape-transport contrat circuit
prevents any tape motion.
@ PAUSE lever
For ingtant stop depress the lavar in record or playback mode
(The PAUSE lamp will light). A slight push upwards releases the
fever again.
@ TAPE SPEED solector
For critical recordings, when extended frequency rasponse
and dynamic range are required. 15 ips (38 cm/s) is recommended.
Tiia.ips {}9emis) wil still yield excellent sound quality white
saving tape:
8
© REEL SIZE selector
‘Salect the optimum rewind tancion and reel ‘torque for the reels
used: The 1O1/2 position is for 101/2-inch {270mm} retls, and 7
is for 7-inch (180mm) or S-inch (120 mm) reels. Use the same
kind of reel {size and hub diameter) for both supply and teke-up
side.
@ Tape counter
@ Function buttons
“44 rewind, m stop, p> forward, snd Pp fast forward; these
buttons can be depressed at random to change tape motion from
normal to fast wind and vice versa,

APE THREADING
ite
the
some
Kind
of
reels
(size
end
hub
diameter)
for
both
supply
@For
the
101/2-Inch
ree!
supplied
neither
reel
adantor
ner
spacer
ad take-un is required.
Place
en
empty
reot
on
the
take-up
(right)
side
and
a
full
rea!
Use
the
supplied
reel
adaptors
RAD-10
as
illustrated
to
install
‘on
the
supply
{left}
side.
10t/2-inoh
(270
mm}
metal
reels.
Lock
the
reels
as
illustrated.
Note:
Oo
not
use
the
spacers
for
101/2-ineh
plastic
reels.
Reel holder
|. Thread the tape as illustrated. Be sure to pass the tape under Reel spingle
the tension arm guides, and above the fixed tepe guides.
Reel adaptor
“Turn the outer knob to secure the real to the adaptor.
Tom the inner knob to secure the ree! to the spindie,
€
va
4, Rotate the reels to take up tape slack untit the tension arms
ata
in
thelr
lifted
(operating)
position.
Noto:
When
threading
a
tape
make
sure
that
the
function
buttons:
44, and DP are roleased (Press the MM button}. IF any of
these buttons is depressed and power is on, the tape motion will
start a8 soon as one of the tension erms is moved into operating
position.

RECORDING AND PLAYBACK
The following six control setting should be checked before any Fundamental Steps
recording and playback to prevent operating errors oc undesired
effects, The function of each switch Is explained on page 7.
and 8.
During normal operation {record as well as playback} keep the six
controls in the following positions:
@ REC TIMER LOCK lever .....-unlacking (upper) position.
@ Microphone ‘ATTenustors ....OFF (pushad-in position of each.
MIC LEVEL contrat.
Only for those channels to be
recorded: REC; for the other
ehannels or during playback:
Pa.
@ REC MODE switches.
® PAN POT switch... OFF.
@ HEADPHONE owitch . <4 CH (2 CH).
@ Playback level controls .......Center position forthe channels
(f and & PBLEVEL) to be used and fully counter
clockwise position for the chan-
nels not to be used.
@ Turn the POWER switch on.
@ Thread 9 tape. Make sure that the tension arms are in oper-
ating position
@ Set the tepe counter "0000" by deprassing the reset button.
© Switch the REEL SIZE selector to the appropriate position.
© Sot the TAPE SPEED selector at dasirad.
© Sot the BIAS and EQ selectors according to the tape used:
cas
BIAS solector | £0 selector Tapes
SONY SUPER 180, SUPER A
TDK 150
SCOTCH 160
Other 150-type' tapes
i
\
|
Gon sun
|
Low NORMAL
}
specia, | MAXELLLNE 35
sea AGFA PE 36
BASF LP 35, 35 LH
SCOTCH 203, 206
Hie TDK SD 160
NORMAL }
For recording select proper setting of BIAS and EQ switches. For
playback select EO proper setting.
‘The above six fundamental steps are common to any operation.
For the next staps proceed 20 one of the following paragraphs,
whichever is appropriate: 4-Channet Recording, 2-Channel Record-
ing, Playback (4 CH, 2 CH}, or Mono Recording and Playback.
10

4-Channel Recording
mage omecel eae
|
‘The input jacks (MIC, LINE IN, or both) and REC LEVEL controls of
alt four channels are used. Parform the fundamantal steps @ to
© and continue with the following steps @ to ©.
@ Sot all four MONITOR switches to SOURCE.
© Adjust all four record lavels at thelr rospactive controls. For o
correct record level sotting refer to chapter “RECORD LEVEL
ADJUSTMENT” on page 14.
© Set all four REC MODE switches to REC. The red Jamps in the
WU-metera will light to indicate that the recorder is ready for
4-channel recording,
@ While fully deprassing the REC bution, push the Be button.
‘The cecording will start. Ag the four tracks corresponding to
the four channels cover the full width of the tape, you eannot
tecord on the reverse side of the tape. So you have to rewind
the tape at the end of the recording.
2-Channel Recording
For conventional 2-channel stereo recording only the tront inputs
‘and controls are used. After baving performed the fundamental
steps @ to @, proceed with stops @ to @.
‘Set the Front MONITOR switches to SOURCE.
© Adjust the FRONT REC LEVEL controls. For acorract record lovel
setting refer to paragraph "RECORD LEVEL ADJUSTMENT " on
page 14
@ Set the Front REC MODE ewitches to REC. Tha red lamps in
the FRONT VU-meters wll Ught indicating that the recorder is
raady for 2-chennel recording. Leave the REC MODE switches
of the back channels in PB postion.
® Whilo fully depressing the REC button (The red lamp in the
button will light), push the forward-button pm to start the 2-
channel recording. Now the recording is made en track 1 ond
track 3.
© For reéording on the remaining two tracks, depress thom button
at the end of the tape, reverte the teals and repeat stop 10.
"

Notes.on Recording :
‘After having done a racording with the REC TIMER LOCK lever
pulled down, don't forget to release it as scon as possibie.
Turn all REC LEVEL controls not in use fully counterctockwise to
improve the S/N ratio
‘¢Qnly when the red lamp In the REC button and those in the VU-
meters are lit together, will the channels indicated by the VU-
meter lamps be recording.
Led FRONT —F ick —h
[ a | ay | ae | |
isos
= = 3 3
Set only the REC MODE switches of tha channels used te REC,
and keep the athers in the PB position.
‘#Be careful not to move the REC MODE sviitches white recording.
‘Alf the TC-788-4 outputs ara connectad to amplifier inputs which
are not controlled by a monitor switch, da at sét the araplifier
input selector to this input while recording. Otherwise oscillation
may occur since the recorder output signals return to its inputs
Ywough the amplifier. If this happens, reduce the PB LEVEL
contol until you have chenged the amplifier input-selector setting
to another position.
lt you re-record on a previously recorded tape, sithar erase the
tape fully (see page 19), or use only the PAUSE button to con-
vol the tape motion, because a tiny portion of the previously
recorded sound will not be erased when the stop: and start-
functions are used.
As arule, the PA LEVEL controls should be in center position
while recording. This position will prevent failure when acci-
domly adjusting the record level with the MONITOR switches
set to TAPE, If this should happen with the PB LEVEL controls
at MAX, the racard level wilt be too low and thus the S/N-ratio
will deteriorate, and with the controls set to too low, the distortion
figure wall be very high because of oversaturation of the tape.
2
Playback (¢ CH, 2 CHI
For 4-channel playback, front and beck output jacks ond tevel
controls ate used, whereas for 2-channel playback only the front
jacks and contro!s ate needed. Continua tho six fundamantal
‘steps (on page 10) with the following four steps:
@ Set the amplifier input selector to the position where the TC-
788-4 is connected,
© Set all four REC MODE switches to PB.
@ For 4-channel playback move all four MONITOR ewitches to
TAPE.
For 2-channel playback sot only the front switchos to TAPE
‘and leave the back switches in the SOURCE position.
® Push the p> buttan, and the playback will start.
in case of conventional 2-channel playback, reverse the reels
at the end of tape and push the Be button once more.
Notes on Piaybact
‘© Playback is possible with the REC MODE switches in the SYNGRO
RAK positions. ut es in this case the playback signal i¢
amplified by the synchce track amplifier, the sound quality will
deteriorate.
(Tapes recorded with 10 high or too low a record level ean be
played back on the TC-788-4 by adjusting the PB LEVEL con-
ols.
eif SLA oF other lows noise tepe is playad beck with the EQ
selector in NORMAL position, tho output will be increased by
about 2.848. On the other hand, with w normal tape and in
the SPECIAL setting. the output will be too low by tha same
mount (2.5 d6}. This is the only effect of the EQ selector dur-
ing playback.
‘If you have made 4-chennel connections, but want to do 2-chan-
nel playback, turn the Back P@ LEVEL controls fully counter-
clockwise.

Mono Racording and Playback
‘Mone recording and playback procedures are essentially identical
‘with, those for stareo except for the channels used. But attomtion
must be pald to tha following points.
In case of recording all tracks In succession :
‘© Only the LF and RF jacks and contrats are used, one after the
other {Refer to the following chart)
eArthe end of each track, do not rewind the tape but reverse
the raei positions.
“Record | Playback
es a a . ae -_
MIC oF LINE IN
beled
Laie
Ree
wore
REC
LEVEL
Output
connes-
|
wonton
switch
|
PB
LEVEL
control
sequence | cannection | switch tion
control |
= it 4 ; I
Track 1 H : LF to TAPE, | LF PB LEVEL control,
-
Ce
eto
pe,
|
Left
FRONT
LEFT
FRONT
|
i
others
to
Turn
all
others
fully
Track 4 | ‘neu dacs jorhers te. output SOURCE } counterclockwis
BF to TAPE, TF PB LEVEL control.
eT FRONT te recog| | AlGNEFRONT RIGHT FRONT | ay othors to Turn at! others fully
Track 2 | Mut lac ogera to outpa SOURCE counterclockwise,
The sofest method to distinguish betwoen ths two ends of 2 tene
(and thus betweon track 1 and 4, of 2 and 3, respectively) is to
make notes of tha color of the outer leader tape together with
the notes concerning the contents. If you use a tape brand where
the numbers 1 of 2 are printed on each reo! side, you may use
these numbers as well, but in this case you must be very careful
over to let the take-up reel show a different number from the
supply raol.
‘Thread the tape which is to be erased.
. Turn all MIC and LINE REC LEVEL controls fully counterclock~
wisa, or disconnect all inputs, of switch alb signal sources off
‘and disconnect the microphones only.
3. Set all four REC MODE switches to REC.
4. With the REC button depressed, push the Pp button. Now the
tape is being erased completely (full track). The tape speed of
1Bips i recommended.
‘eFor quick erasure, use 2 bulk eraser.
13

REGORD LEVEL ADJUSTMENT
If your sound source is an FM-broadcast or a record, the larger
controls have to be used for adjustment of the record teval, and
the smaller controls for microphone recordings.
Please don’t forget to turn all leveb controls not in use to MIN in
order to achieve the best S/Nratio possible.
REC LEVEL
y For fing sources
asi For mic (Pull 10
‘MAX gotivate the mic
attenvator)
Adjust the record levels of each channel white watching the neadie
of the corresponding VU-meter and listening to the toudest
passage of the program you want to record. When recording at
7iJ2 tps. avoid swinging of the needies into the red zones (O—
+3 VU) because this will lead to distortion. On the other hand
tha levels should be as close 35 possible to OVU to make full use
of the large dynamic range, Otherwise tape hiss will be consider-
ably increased during playback. When using the 15~ips speed,
staying of the needles within red zone is still tolerable, as the dyna-
mic ranga becomes widor than that of 7¥2 ips.
x % ie] [e)
ASI SIE
“oo low Jovel” Too bigh level Proper tovel level
ingisyh enpatseuna | Gt TE poe at is
fatoteil be, Swi be cistorted,)
poor)
v0
3 = Input signal: 10 kHz
Bo ‘Sipe
zg 7Kies
é ‘With SLH tape
Tao
Input fevel in VU
But be cautious with peaks of short duration out of a relatively
low record level: as the needles of the VU-meters cannot follow
them because of theit inertia, they wit! show levels much smaller
than the actual levels (up to 12 or 142). In case of extreme
short pulsas your ears might 2s well be unable to recognize
distortion, so you should nat worry too much.
14
Recording of FM broadcasts or records is relatively simple because
broadcast stations and record companies use standardized limiters,
Yo reduce the dynamic renge of the original sound source.
With hardly any exceptions their program has been recorded on
tape at least once in 2 previous stage. You can record with 2
Fixed lavet once you have established the proper LINE REC LEVEL
‘settings, one matching the output level of your cartridge and the
‘other one matching the output level of your tuner or receiver.
Usually there is @ fixed relation between the time signal strength
‘and full modulation of a given FM station, in most cases the time
signal being 2 or 348 lower. Once you know their relation at
your favorite station this will provide a good mark for the REC
LEVEL conteol settings.
A little more care has to be taken in case of live recordings, The
dynamic range is undiminished by any limiter. and a small move-
mont may change the distance between sound source and micro-
phone, thus changing the signal level even when repeating an
identical passage. Above all consideration has to be given to
the fect that tape saturation and distortion at higher frequencies
‘occur at lower levels, which may be especially troublesome in case
of piano recordings eto, To make things even more complicated,
there is the danger of overloading the microphone amplifiers.
But haying acquired a line bit of experience, you will bo quite
following points.
tting the level of the largest
1, Allow some more headroom by
input signals to ~3 or —8 VU.
2. As in contrast to the line inputs the microphone racord level is
‘adjusted behind the microphone ampiiti @ MICrophone
ATTonuator switch to avoid turning the level controls 100 far
counterclockwise and overloading the amplifiers, when large
Input signals like bass or drum sounds are expected. By pull-
ing the MIC REC LEVEL knobs outwards the input signals will
be attenueted by 2048 before they reach the microphone
‘amplifiers. Overloed distortion will bo avoided by this {in fact
a safety margin of approx. 13.48 remains above the highast
output level of all Sony microphones}, and the setting of the
ove! ean be done more oasily, because the controls
around the center position.
~2de4—-
= 12.8084
2208-4
.
ATT. OFF
o
The dj range
imum out
namic
38
ATT: ON
iy
Normal input
feval of TC-788-4
nic amp = 60.48
{0.775 mV).
—604B-

Anyway, whether you are recording line or microphone sources,
the safest method to avoid any failure is to listen with a pair of
good headphones ta the results of your recording (MONITOR
switches sat to TAPE). 8y comparing the recorded sound with
the original {SOURCE} you will easily detect sny distortion and can
raduce the record level accordingly. Furthermore, this comparison
will warn you against ditty heads (loss of high frequencies) and
dirty o faulty tapes {drop outs}.
source
‘iouroa Hl
TAPE f sclector
Recording
Ampttier
putput sg
Tope input
Line input @ Tape recorder
Line output
REC LEVEL
control
Monitor
SOLACE § selector
8 LEVEL control
Eras Playback
head
sre
For lina .stereo recordings it will usuatly be best to adjust the
record lovel of the channel with the larger signals first and to
move the control of the second channel into the same position, so
that a mono signal seems to come from the canter. Any unbal-
ances thervaftar will be deliberately caused by the record com-
pany of FM-station, In ease of microphone recordings balance
the channels to produce the desired impression.
For quadraphonic 4-channel recordings this question cannot be
answered generally, #8 too much cepends on your intantions. But
ln most cases it will be best to set the record level of each chan:
rel separately for optimum dynamic range. if you use the back
‘channels only for ambient sounds, you will have to seduce for
reproduction the Back channel PB LEVEL, or change the front!
back-balance control of your amplifier, or use both togather, until
a normal sound is achieved.
Do not change the racord level once the recording has started, as
this will easily be audible during playback, especially, when the
stereo balance is changed. if adjustment becomes necessary
after the beginning of tha recording, it will be advisable to wait
Until a break or a pausa between movements occurs or 2 soloist
has finished his turn,
15

SPECIAL OPERATIONS
Microphone and Line Mixing
‘The TC-788-4 provides a MIC-and-LINE mixing facility for each
channel.
1, Connact the program sources to be mixed to the correspond
ing MIC of LINE INputs, Tho mic- and line-inputs belonging to
‘one channel an now be mixed.
2, Set the MONITOR svitchas to SOURCE.
2. Adjust the desited mixing levels while monitoring through
headphones, The VU-meters indicate the composite recording
evel of line- and mic-inputs.
4. Start the rocdrding as explained in chapter "4-Chsanel Record-
Ing” on page TI.
Mixing with the Use of the Panoramic Potentiometar
{PAN POT)
The PAN POT was designed to utilize the otherwise idle beck
channel amplifiers for normal 2-channel stereo recordings in the
most versatile manner. AS 2 result, up to two MIC and two LINE
INputs can bo mixed onto-each front channel at the same time, or
‘up to three MIC and three LINE INputs onto one front channel.
‘Tho PAN POT Is especially useful whon the seperate recording of
each instrument of a jazz or rock group is required, or tor making
balanced recording with the microphanes in cases that osually
‘cannot be balanced, or when recording one or two soloists against
the stereo background of an ensemble of orchestra, In eny case
the PAN POT exactly defines the position of sound sources be-
tween the stereophonic laft and right.
Depa teva. —
uine~G@-aie KR
po
Fo'tonatores
ori
Ae 4
oO §
Gontrot me
Volume of the
‘added sound
MN an
Select tha
tion to
\
OFF
LB inputs
16
How to use the PAN POT:
1. Connect the signal sources whose acoustical position you went
to change to the LB or RB MIC or LINE INputs. The LF and
RF input-positions cannot be influenced.
2. Insert headphones to the Front 2 CH HEADPHONE jeck and
set the HEADPHONE ewitch to 4 CH (2 CH).
3, Move all four MONITOR switches to SOURCE.
4. Adjust the front channel record level with the Front REG LEVEL
controls.
5. Set the PAN POT switch to ON. The green PAN POT lamp
‘will Eight to indicate that the pancramie potentiometers ars
eotivated.
6. While listening through headphones regulote the strength of
the added signals at the Back REC LEVEL controls, and their
position between left and right at the PAN POT controls, This
can be carried out separately for each-back channel. Turning
of one of the PAN POT controls fully to the LF-position feeds
the signal of the respective channel to the feft front channel
‘only, turning to AF to the right front channel only. At © the
signal is distributed evenly between LF ond AF. In betwoen all
other mixing positions ean ba taken up continuously.
‘01 very high input signals should occur during live recording with
microphones, the MIC ATTenuater of each channal can be used
separately to prevent overload distortion of the mic amptitiers.
‘#The back VU-meters show the signal strength of the back chan-
nels only, whereas the front VU-meters show the strength of tho
composite signals, j.e, the actual recording level.

Synchro-Track Recording
™ Syneliro-track" describes the possibility of switching the record
head on a certain track from recore to playback by simply moving
the REC MODE switches. Thus it becomes possible to use the
record head simultaneously for the playback of one or more pre-
viously recorded tacks and for the new recording on one or more
of the remaining tracks.” As there is no time lag between record-
ing and playback, this allows precise timing for the newly added
materials and opens many possibilities for tape editing.
‘The recording can be started on any channel
1. Record the basic program {in the following caited program A)
‘on ane or more of the four channels.
2, Rewind tha tape to the beginning of program A.
3. Set the REC MODE switches of the channels belonging to the
previously recorcied program A to SYNCRO TRAK and the
respective MONITOR switches to TAPE
4, Connect the source of the program now to be added (program
8) to one (or more) of the unrecorded channels, and set the ro-
spective REG MODE switches} ro REC and MONITOR switches)
to SOURCE.
8. Set the REC MODE switches of the channels completely unused
(neither for record nor for playback: LB and RB in the example
given below) to PB and thair MONITOR switches to SOURCE.
@. Uae headphones and solect a jack and HEADPHONE switch
setting most appropriate to your intentions, (Most probably
this will bo FB and any of the two jacks). If program & is
‘ot recorded through microphones. you may use speakers, 100,
Depress tho REC button firmly and push the Be button. Re-
cording of the new material now begins. As by means of the
SYNCRO-TRAK function of the AFC MODE switch recording
‘and playback occur via the same record head, programs A and
B ate on the identicat tape portion (though on different tracks)
‘and can thus be pertectly synchronized.
8, When repeating steps 2. to 7, you can still add another new
program.
7
‘#As in tho REC position of the REC MODE switches the erase
heads eradicate all praviously recorded material on the same
track, be very careful whan selocting the channels on which you
want to record program B, and set only the switches of these
channots 10 REC.
‘sf you are not yet satisfied with the results of your synctiro-track
recording, you can orase program B and add a new one by
simply rewinding the tape end repeating step 7.”
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Timer-activated Recording
‘Aulomatic recordings may be made with a commercially available
timer.
4. Select the desired FM station.
2. Thread a tape and adjust the recording levet.
3, Switch the REC MODE switches of the desired channels to
REC and leave the others in the PB position.
A. With the REC button depressed, mova the REC TIMER LOCK
Fever down.
8. Connect the TC-788-4 power cord to the timer, and preset the
desired time.
6. Push the POWER switch to ON, and depress the Be button.
Now the TC-788-4 is ready to start an FIM recording automati-
cally.
Noto: Do not forge? to release the REC button by moving the
REC TIMER LOCK lever upwards after the end of the
automatic recording.
For automatic playback, thread 9 tape, set all REC MODE switches
to PB and all MONITOR switches to TAPE and perform steps 5
and 6.
‘Wall outlet
@
18
About Tracks and Channels
‘The number of channels of @ given music system (or pert of i) is
the number of completely separate, parallel signal paths covering
‘the full audio frequency range that'can be used at the same time.
‘So a quadrephonic system with its front and back, left and right
signals comprises four channels, end a stereo system with Its
‘separate left and right signals two channels.
‘The number of tracks describes the number of stripes of magnetized
information across a tape that can be recorded and played back
‘soparetely, regardless of their direction or whether the information
js synchronous (quedraphonic, stereophonic} or completely a syn
chronous (different mono-programs). Of course the number of
‘channels can. never be larger than the number of tracks for a
given tape deck.
If you look at the record head of the TC-788-4, you will see four
darker belts, the outer surfaces of the cores. When the tape
passes these portions, it will be magnetized in tracks with exactly
the same width ws the bolts, So you have recorded a 4-track 4-
chanael tape. As the whole width of the tape has been used. it
‘cannot be reversed. Starting from the top, these tracks contain
the channels LF, LB, RF and RB.
Mf every second belt is missing or only they a
remaining two are in the same position and have the sume width,
you can record only two tracks at a time in one direction (Track 1
for Land track 3 for Ri). ut after having the tape reversed, the
‘same dark belts of the heads touch the space previously
recorded. (Now track 4 is for Land track 2 for R.) As a result,
‘you will have recorded four tracks, but becauso of the raversing
process you can listen to only two tracks at one time, so iti
4-track 2-channel tape.
When the record head has only two darker belts and the:
wider than those of the TC-782-4 so that they cover the whole
width of the tape, the tapes recorded by such haads are called 2-
track 2-channel, and they can be played in one direction only.
The uppor track is for the left chanel, and the lower for tho right
chennel.
With a slight Joss in SiMt-ratio, 2-track 2-channel tapes can be
played back on 4-channel tape decks with the deck in 4-channel
playback
mode
and
the
amplifier
in
stereo
(F-+B)
moda.
On
the
‘other hand, quadraphonie 4-track tapes can be played on a 2-track
‘stereo deck, but the sound will be unbalanced, as tho teft channel
contains only part of the beck information and the right channel
only part of the front information.
track 2-chaninel and 2-track 2-channel tapes cannot be ex:
changed. (Even when using such tapes for new recordings,
strongly advisable first to erase them completely on the deck on
which they had bean previously recorded, or with a bulk eraser.)
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EDITING
There are two main ways of tape editing: editing by tape duplica-
tion and by splicing. {ln some special cases synchro-track record-
ing may be used as another form of editing). Their major
advantages and disadvantages are 2¢ follows:
Editing by duplicating
Tapes recorded in two directions can be edited.
‘Cassette programs can be included in the editing process.
@ More creative resutts can be obtained by using the mic-and-line
mixing’ facility.
‘ef the originat programs are recorded in various levels, they should
be copied. to the same level by controlling the record level of the
slave recorder (or the output level of the master recordsr).
but
Two recorders’ ara raquired.
Distortion and especialy noise will be increased considerably
while duplicating.
Editing by splicing
As splicing doas not increase noise or distortion, it is the most
common technique used by professionals, but it requiras quite
some skiN for noise-free splicing.
‘# Program switching can be done very accurately.
but
‘# Only tape recorded in one direction can be spliced.
‘@ Mistakes can hardly be correcte
Thera is a lot of wasted ta
According to your circumstances or preferred editing results, either
way ¢an be used or the two can be mixed. in either case experi-
‘ence will provide the required skill far noita-tres and accurate
editing result
Betore editing, play the original tape thoroughly, and note the
Tape Counter number where the unwanted sounds (narration or
commercials, pop noise, etc.) are focated. Then go back and
proceed with editing in either way,
Duplicating Procedura
1. Connect two recorders as shown on page 5.
2. Start the master recorder in playback mode and tho slave
recorder In record mode. At the unwanted portion, stop the
slave recorder with tha PAUSE lever until the unwanted pass-
agus have passed or you have changed tha tape. The cueing
facility on the master recorder will be very useful for pracisaly
locating the start portion of the program.
Notes
‘To stop the tape, the PAUSE lever should be used to prevent
possible click noise.
eBest results are obtained when both recorders are of equal
auality, but if one should be inferior, use the better ona for tha
playback process.
1. Advance the tape to the counter number to be spliced, and
stop tha tape with the PAUSE lever in playback mode,
2, Move the tape across the playback head back aad forth by
‘turning both supply and take-up reels by hand.
3. While listening 10 cue sound, find the correct portion to be
spliced, and carefully mark it at the position of the playback
head on the outer side of the tape with a soft colored pencil.
fYeliow witl be most distinctive.)
Note: Take care not to get axcess marking material on tha heads.
Any staing on the heads will causa contamination and impair good
tape-to-head contact.
Splicing Tape
Use splicing tape and 2 demagnetized pair of acissors.
Note: Do not use ordinary cellophane tape as it tends to spoil
recording tapes.. Also avold using magnetized scissors or razor
blades. Magnetized instruments will cause a “click” or “ pop”
at the spliced portion.
Take care not to unnecessarily touch the portion of the tape to be
spliced. Even invisible traces of grease and sweat from your
tingors will hinder a good sticking.
1. Neatly overlap the tapes to be spliced and cut diagonally.
2. Place the two diagonal tape ends together, outer side up, on &
flat surface. Be careful to make ends meet but not overlap.
3. Apply # piece of splicing tape diagonally over the aligned end:
‘and press it firmly.
4, Trim off the excess splicing tape, slightly cutting into the tape.
19

MAINTENANCE
Cleaning Heads and Tape Path
Generally, cleaning heads after evary 10 hours of operation will
be sufficient. However, all surfaces over which tape tavels should
be cleaned before’ making high quality recordings.
Dirty heads and tape path will cause:
‘eLoss of high frequency response which results in poor sound
quality.
‘@ Loss of sound volume in recording and pleybsck.
Dropouts.
A Increasa of wow and flutter.
‘@ Unsatisfactory results in tape erasing.
For better access to the heads pull off the lower part of the head
cover, The upper part is better left In place, because it protects
the fixations for the eritical head
‘Tako the supplied head cleaning aid {either ribbon or a tip) acd wipe
the heads and tape path. If the deposits are difficutt to remove,
foisten the ribbon with danatured alcohol or head cleaning
sohution,
‘@ Bo oiireful not to scratch the head surface:
5a
‘For easier cleaning of the pinch rollers and capstans rotate them
by holding one of the tension arms in operating position and
pushing the p> button.
20
Demagnotizing Heads
Residual magnetism will gradually build up on the heads through
continuous use end cause an increase of tape noise while record-
ing, and eresure of high frequencies or hiss build-up on your
prerecorded tapes. The heads and metallic parts of the tepe path
should therefore be demagnatized after every 40-50 hours of
‘operation with # commercially available head demagnetizer.
Lubrication
To maintain the optimum performance of the TC-788-4, consult
your nearest Superscope Service Station once a year for lubrication
‘ang inside check.
Cleaning of the Cabinet
Clean the cabinet, pane! and controls with @ soft cloth. If finger
prints, food and beverage stains, etc. 90 difficult to remove, ose
‘2 damp cloth or a mild soap solution. Bo not use any type of
scouring powder. abrasive pad, or solvent.